Hong Kong's worst red tide

A dinoflagellate referred to as Gymndinium mikimotoi (formerly referred to as Gyrodinium aureolum) produced copious amounts of a sticky mucus during its peak abundance in March and April of 1998. The mucus coated the gills of fish and shellfish at many locations in Hong Kong. The present report is the first to document temporal changes in the population density of this dinoflagellate during bloom development in Hong Kong at a site near the Lamma Island fish farms. Phytoplankton samples were taken at Mo Tat Wan ( Fig. 1 ) near Lamma Island each week before, during and after the G. mikimotoi red tide. Changes in the abundance of the dominant species as well as some of the subdominant species as the red tide developed were examined and the results plotted. The study also attempts to exploain why mucilage production by G. mikimotoi might reduce its chances of being consumed by predators.